Enhanced resistance to bacterial and oomycete pathogens by short tandem target mimic RNAs in tomato.

Nucleotide binding site leucine-rich repeat (NLR) proteins of the plant innate immune system are negatively regulated by the miR482/2118 family miRNAs that are in a distinct 22-nt class of miRNAs with a double mode of action. First, they cleave the target RNA, as with the canonical 21-nt miRNAs, and second, they trigger secondary siRNA production using the target RNA as a template. Here, we address the extent to which the miR482/2118 family affects expression of NLR mRNAs and disease resistance. We show that structural differences of miR482/2118 family members in tomato (Solanum lycopersicum) are functionally significant. The predicted target of the miR482 subfamily is a conserved motif in multiple NLR mRNAs, whereas for miR2118b, it is a noncoding RNA target formed by rearrangement of several different NLR genes. From RNA sequencing and degradome data in lines expressing short tandem target mimic (STTM) RNAs of miR482/2118, we confirm the different targets of these miRNAs. The effect on NLR mRNA accumulation is slight, but nevertheless, the tomato STTM lines display enhanced resistance to infection with the oomycete and bacterial pathogens. These data implicate an RNA cascade of miRNAs and secondary siRNAs in the regulation of NLR RNAs and show that the encoded NLR proteins have a role in quantitative disease resistance in addition to dominant gene resistance that has been well characterized elsewhere. We also illustrate the use of STTM RNA in a biotechnological approach for enhancing quantitative disease resistance in highly bred cultivars.

Complex antioxidants in a randomized single-blinded study of memory in seniors.

INTRODUCTION: Oxidative injury to the brain and aging are theoretical co-causes of Alzheimer's Disease (AD). Amyloid plaques and tangles are then secondary phenomenon. The preclinical state would then be 'normal' elderly. METHODS: A potent complex antioxidant (antiOx) was tested against a popular one-a-day multivitamin (mV) in a randomized single blind design in 'normal' senior subjects over 6 months. Memory testing was done at baseline, 1, 3, and 6 months. The generalized estimating equation (GEE) approach was used to compare the change score of NLT100 and 20WR between two groups over time. RESULTS: Analysis of the antiOx group (30 subjects) demonstrated significant improvement in declarative memory (change score for NLT100 at month 6 = 6.36 p < 0.0001) and working memory (change score for 20WR at month 6 = 3.23, p < 0.0001). A change-score analysis over 6 months suggests possible neurogenesis in the antiOx group. The mV group (33 subjects) had a change score of the NLT100 and 20WR on the sixth month of 2.20 and 0.32 (p = 0.07, 0.35). CONCLUSIONS: A complex antioxidant blend, sold as an over-the-counter (OTC) supplement, can improve memory in elder subjects. Antioxidants may be beneficial in AD and other neurodegerative diseases.

A deletion variant partially complements a porin-less strain of Neurospora crassa.

Mitochondrial porin, the voltage-dependent anion channel, plays an important role in metabolism and other cellular functions within eukaryotic cells. To further the understanding of porin structure and function, Neurospora crassa wild-type porin was replaced with a deletion variant lacking residues 238-242 (238porin). 238porin was assembled in the mitochondrial outer membrane, but the steady state levels were only about 3% of those of the wild-type protein. The strain harbouring 238porin displayed cytochrome deficiencies and expressed alternative oxidase. Nonetheless, it exhibited an almost normal linear growth rate. Analysis of mitochondrial proteomes from a wild-type strain FGSC9718, a strain lacking porin (ΔPor-1), and one expressing only 238porin, revealed that the major differences between the variant strains were in the levels of subunits of the NADH:ubiquinone oxidoreductase (complex I) of the electron transport chain, which were reduced only in the ΔPor-1 strain. These, and other proteins related to electron flow and mitochondrial biogenesis, are differentially affected by relative porin levels.

Functional characterization of an N-terminally-truncated mitochondrial porin expressed in Neurospora crassa.

Mitochondrial porin, which forms voltage-dependent anion-selective channels (VDAC) in the outer membrane, can be folded into a 19-ß-stranded barrel. The N terminus of the protein is external to the barrel and contains α-helical structure. Targeted modifications of the N-terminal region have been assessed in artificial membranes, leading to different models for gating in vitro. However, the in vivo requirements for gating and the N-terminal segment of porin are less well-understood. Using Neurospora crassa porin as a model, the effects of a partial deletion of the N-terminal segment were investigated. The protein, ΔN2-12porin, is assembled into the outer membrane, albeit at lower levels than the wild-type protein. The resulting strain displays electron transport chain deficiencies, concomitant expression of alternative oxidase, and decreased growth rates. Nonetheless, its mitochondrial genome does not contain any significant mutations. Most of the genes that are expressed in high levels in porin-less N. crassa are expressed at levels similar to that of wild type or are slightly increased in ΔN2-12porin strains. Thus, although the N-terminal segment of VDAC is required for complete function in vivo, low levels of a protein lacking part of the N terminus are able to rescue some of the defects associated with the absence of porin.

The Cold War and Phage Therapy: How Geopolitics Stalled Development of Viruses as Antibacterials.

The bacteriolytic character of bacteriophages was employed as antibacterial therapy almost from the time of their discovery in 1917. In the United States, phage therapy was sporadic during the 1920s and 1930s but had dwindled into obscurity by the post-WWII period. This demise of phage therapy has traditionally been attributed to the superiority of antibiotics, discovered and first used during the war years, but this explanation is complicated by the fact that phage therapy outside the United States has had a longer and more successful life, especially in the countries of Eastern Europe. This review considers another, probably synergetic factor that was specific to the medical uses of phage in the United States: the geopolitical climate fostered by the Cold War reaction against Soviet science and its associated specter, socialized medicine. This analysis suggests that even such a purely scientific matter involving bacterial viruses cannot escape social forces and political ideologies.

Fatigue in Post-Acute Sequelae of Coronavirus Disease 2019.

Fatigue from post-acute sequelae of coronavirus disease 2019 is a complex constellation of symptoms that could be driven by a wide spectrum of underlying etiologies. Despite this, there seems to be hope for treatment plans that focus on addressing possible etiologies and creating a path to improving quality of life and a paced return to activity.

A C-Terminally Truncated Variant of Neurospora crassa VDAC Assembles Into a Partially Functional Form in the Mitochondrial Outer Membrane and Forms Multimers in vitro.

The voltage-dependent anion-selective channel (VDAC) is a porin in the mitochondrial outer membrane (MOM). Unlike bacterial porins, several mitochondrial ß-barrels comprise an odd number of ß-strands, as is the case for the 19-ß-stranded VDAC. Previously, a variant of a VDAC from Neurospora crassa, VDAC-ΔC, lacking the predicted 19th ß-strand, was found to form gated, anion-selective channels in artificial membranes. In vivo, the two C-terminal ß-strands (ß18 and ß19) in VDAC form a ß-hairpin necessary for import from the cytoplasm into mitochondria and the ß-signal required for assembly in the mitochondrial outer membrane resides in ß19. The current study demonstrated that the putative 18-stranded ß-barrel formed by VDAC-ΔC can be imported and assembled in the MOM in vivo and can also partially rescue the phenotype associated with the deletion of VDAC from a strain of N. crassa. Furthermore, when expressed and purified from Escherichia coli, VDAC-ΔC can be folded into a ß-strand-rich form in decyl-maltoside. Size exclusion chromatography (SEC) alone or combined with multi-angle light scattering (SEC-MALS) and analytical ultracentrifugation revealed that, unlike full-length VDACs, VDAC-ΔC can self-organize into dimers and higher order oligomers in the absence of sterol.

Origami in outer membrane mimetics: correlating the first detailed images of refolded VDAC with over 20 years of biochemical data.

Mitochondrial porin forms an aqueous pore in the outer membrane, through which selective passage of small metabolites and ions occurs, thereby regulating both mitochondrial function and cellular respiration. Investigations of the structure and function of porin have been performed with whole mitochondria, membrane vesicles, artificial membranes, and in detergent solutions, resulting in numerous models of porin structure. The mechanisms by which this protein functions are undoubtedly linked to its structure, which remained elusive until 2008, with reports of 3 high-resolution structures of this voltage-dependent, anion-selective channel (VDAC). The barrel structure is relatively simple yet unique: it is arranged as 19 anti-parallel beta-strands, with beta-strands 1 and 19 aligned parallel to each other to close the barrel. The N-terminal helical component is located within the lumen of the channel, although its precise structure and location in the lumen varies. With the basic barrel structure in hand, the data obtained in attempts to model the structure and understand porin over the past 20 years can be re-evaluated. Herein, using the mammalian VDAC structures as templates, the amassed electrophysiological and biochemical information has been reassessed with respect to the functional mechanisms of VDAC activity, with a focus on voltage-dependent gating.

The negative regulator SMAX1 controls mycorrhizal symbiosis and strigolactone biosynthesis in rice.

Most plants associate with beneficial arbuscular mycorrhizal (AM) fungi that facilitate soil nutrient acquisition. Prior to contact, partner recognition triggers reciprocal genetic remodelling to enable colonisation. The plant Dwarf14-Like (D14L) receptor conditions pre-symbiotic perception of AM fungi, and also detects the smoke constituent karrikin. D14L-dependent signalling mechanisms, underpinning AM symbiosis are unknown. Here, we present the identification of a negative regulator from rice, which operates downstream of the D14L receptor, corresponding to the homologue of the Arabidopsis thaliana Suppressor of MAX2-1 (AtSMAX1) that functions in karrikin signalling. We demonstrate that rice SMAX1 is a suppressor of AM symbiosis, negatively regulating fungal colonisation and transcription of crucial signalling components and conserved symbiosis genes. Similarly, rice SMAX1 negatively controls strigolactone biosynthesis, demonstrating an unexpected crosstalk between the strigolactone and karrikin signalling pathways. We conclude that removal of SMAX1, resulting from D14L signalling activation, de-represses essential symbiotic programmes and increases strigolactone hormone production.

Mechanisms Underlying Establishment of Arbuscular Mycorrhizal Symbioses.

Most land plants engage in mutually beneficial interactions with arbuscular mycorrhizal (AM) fungi, the fungus providing phosphate and nitrogen in exchange for fixed carbon. During presymbiosis, both organisms communicate via oligosaccharides and butenolides. The requirement for a rice chitin receptor in symbiosis-induced lateral root development suggests that cell division programs operate in inner root tissues during both AM and nodule symbioses. Furthermore, the identification of transcription factors underpinning arbuscule development and degeneration reemphasized the plant's regulatory dominance in AM symbiosis. Finally, the finding that AM fungi, as lipid auxotrophs, depend on plant fatty acids (FAs) to complete their asexual life cycle revealed the basis for fungal biotrophy. Intriguingly, lipid metabolism is also central for asexual reproduction and interaction of the fungal sister clade, the Mucoromycotina, with endobacteria, indicative of an evolutionarily ancient role for lipids in fungal mutualism.

The management of agitation in demented patients with propranolol.

Congress and the FDA have strongly suggested that tranquilizers and antipsychotics not be used in agitated demented frail elderly patients. The medical profession has not moved away from the tradition of antipsychotic sedation of such patients. Use of 'modern second generation low dose' antipsychotics continue to be the standard of care. Propranolol, a non-selective beta-blocker with good penetration of the CNS, is a reasonable and safe alternative to sedatives and antipsychotics. Anti-dementia drugs are complementary to propranolol. A case study which contrasts the two pharmacologic approaches is detailed. A method of estimating delirium-agitation risk in dementia patients (DRN method) is described.

Tacrine, and Alzheimer's treatments.

The story of the development of tacrine began from its synthesis as an intravenous antiseptic in 1940 by Adrian Albert in Australia. In the 1970's William Summers began using tacrine in treating drug overdose coma and delirium. He felt it might have application in Alzheimer's based on work done in England by Peter Davies. In 1981, Summers et al. gave intravenous tacrine to Alzheimer's patients showed measurable improvement. Between 1981 and 1986, Summers worked with Art Kling and his group at UCLA to demonstrate usefulness of oral tacrine in treatment of Alzheimer's patients. The average length of tacrine use in 14 completing patients was 12.6 months and improvement was robust. This sparked controversy in the field. In 1993, after larger studies replicated the positive effect of tacrine, it was approved by the US Food and Drug Administration for treatment of Alzheimer's disease.

Félix Hubert d'Herelle (1873-1949): History of a scientific mind.

The discovery of bacteriophage one century ago by the French-Canadian Félix d'Herelle set off controversies as to the nature of bacteriophage as well as over the priority and credit for this discovery. The background and life of d'Herelle reveals a complex, self-taught outsider in science who was strongly influenced by his admiration of Louis Pasteur, but also his attachment to the philosophical positions of early 17th century philosophers, especially Francis Bacon. D'Herelle left substantial unpublished writings on his philosophical musings toward the end of his life.

Rice perception of symbiotic arbuscular mycorrhizal fungi requires the karrikin receptor complex.

In terrestrial ecosystems, plants take up phosphate predominantly via association with arbuscular mycorrhizal fungi (AMF). We identified loss of responsiveness to AMF in the rice (Oryza sativa) mutant hebiba, reflected by the absence of physical contact and of characteristic transcriptional responses to fungal signals. Among the 26 genes deleted in hebiba, DWARF 14 LIKE is, the one responsible for loss of symbiosis . It encodes an alpha/beta-fold hydrolase, that is a component of an intracellular receptor complex involved in the detection of the smoke compound karrikin. Our finding reveals an unexpected plant recognition strategy for AMF and a previously unknown signaling link between symbiosis and plant development.

Alzheimer's disease, oxidative injury, and cytokines.

Alzheimer's disease is infrequently a genetically driven disease. Rather it is the product of free radical injury inflicted over decades after an initial insult to the central nervous system (CNS). The brain is uniquely sensitive to oxidative injury. A variety of insults to the CNS are now associated with Alzheimer's disease. These include hypertension, diabetes, and head trauma. These then cause a cytokine cascade and microlocalized inflammation in the CNS, that in time results in clinical Alzheimer's disease. By the ninth decade of life over half of the population manifests Alzheimer's disease. Prevention or reversal of this pathophysiology will lie in administration of effective antioxidant therapy with specific treatments when etiologies are known.

Inventing Viruses.

In the nineteenth century, "virus" commonly meant an agent (usually unknown) that caused disease in inoculation experiments. By the 1890s, however, some disease-causing agents were found to pass through filters that retained the common bacteria. Such an agent was called "filterable virus," the best known being the virus that caused tobacco mosaic disease. By the 1920s there were many examples of filterable viruses, but no clear understanding of their nature. However, by the 1930s, the term "filterable virus" was being abandoned in favor of simply "virus," meaning an agent other than bacteria. Visualization of viruses by the electron microscope in the late 1930s finally settled their particulate nature. This article describes the ever-changing concept of "virus" and how virologists talked about viruses. These changes reflected their invention and reinvention of the concept of a virus as it was revised in light of new knowledge, new scientific values and interests, and new hegemonic technologies.

The strange history of phage therapy.

Since the enlightenment, scientists have enjoyed a self-image as rational actors, guided only by reason, evidence and logic. When the Royal Society of London was founded in 1660 it chose as its motto "nullius in verba" (often translated as "on the word of no one") a reference to Horace's Epistles "Nullius addictus iurare in verba magistri…" (being not obliged swear allegiance to any master). Similar to our 21st century contemporaries who embrace the "new evidenced-based medicine," the "virtuosi" of the Royal Society proclaimed a new era in science based only on observation and direct experience.

Mitochondrial dysfunction resulting from the absence of mitochondrial porin in Neurospora crassa.

Porin, the voltage-dependent anion-selective channel (VDAC) in the mitochondrial outer membrane, contributes to metabolism and apoptosis. VDAC function was investigated in Neurospora, an obligate aerobe with a single porin. Porinless strains are viable, with cold-sensitive growth, cytochrome deficiencies and overexpression of alternative oxidase. iTRAQ labeling of mitochondria from a porinless strain and its progenitor revealed a small group of proteins with altered expression levels in the mutant organelles. Porinless Neurospora appears to compensate not by inducing alternative pores, but by altering electron flow and nucleotide metabolism. Transcriptional and post-transcriptional mechanisms contribute to the response, reflecting the extent of porin influence.